X-ray powder diffraction patterns for many interstratified kaolinite/glycolated smectites were calculated by changing combinations of probabilities and transition probabilities of two component layers. Reichweite = 0 and Reichweite = 1 structures were investigated. The calculated d-values were plotted, with PKS (the probability that a smectite layer succeeds a kaolin layer given that the first layer is a kaolinite layer) and PSK as the axes of coordinates. These d-values were then linked into equal d-value curves on a graph. Four equal d-value diagrams for mixed reflections ranging from 34.0 to 17.1 Å, from 8.5 to 7.2 Å, from 6.13 to 5.68 Å, and from 3.540 to 3.401 Å were constructed. Two examples of identifying natural kaolinite/smectite minerals using these diagrams are presented.

Using theoretical profiles of diffracted X-ray intensity for interstratification between layers having d-spacings around 14.3 Å and 10.1 Å, a series of diagrams was derived from which the proportion of 14.3 Å layers (W14) and the probability of passing from a 14.3 Å layer to a 10.1 Å layer (P14/10) can be derived. W14 can be derived independently of P14/10 using the angular distance between reflections situated at 18.2° and 25.4° 2θ (CuKα). Once W14 is determined, P14/10 may be obtained using the angular width of the diffuse reflections between 27° and 34° 2θ. In this case, two different diagrams are proposed for P14/10 determination because experimental X-ray patterns show either one or two diffuse reflections. Comparison of five experimental patterns with theoretical patterns calculated using W14 and P14/10 obtained using these diagrams indicates that the method can be useful for determining W14 and P14/10 in unknown samples. Moreover, the method described is independent of the Lorentz polarization factor and the layer type. The d-spacings associated with the two kinds of layers, however, should be similar (± 1%) to those for which the determinative diagrams were calculated.